Failed emissions...idling and driving issues

[babysirt]

I just bought my first 240SX. It has 246,000 miles. According to the record, it failed its last emissions test 300 miles ago. Here is what I failed:

High Speed Emissions (25mph), RPM:1920HC: Standard=132, Reading=137

Low Speed Emissions (15mph), RPM: 1696HC: Standard=136, Reading=229CO: Standard=0.76, Reading=3.58

I noticed that the car idles at about 950rpm once warm. It also stumbles (as if it was misfiring) every now and then while its idling. While driving it, sometimes it bogs when I floor it.

According to the records, the fuel filter, distributor cap, rotor, PCV valve, plugs, and wires were replaced 11,000 miles ago.

I checked the plugs and they are in good shaped. I checked engine and ignition timing and it is fine. I checked the rotor and cap and they seem to be in good shape. I checked the O2 sensor using Diagnostics Mode II and it checked out ok. The air filter is clean. I'm stomped!

[aris_unlimited]

how is the egr valve?

[Ilvemynissan]

What about the catalytic converter you might need a new one. I didn't see that on the list of parts replaced. I don't know if just that will make you pass though.

[babysirt]

I forgot to include that the Diag. Test Mode II came up with a bad knock sensor.

[Q45tech]

The numbers on the test show [prove] a worn out cat!

[babysirt]

The numbers on the test show [prove] a worn out cat!

Wow, that sucks! And a worn cat causes all the driving symptoms I've been experiencing?

[Q45tech]

Since you didn't provide nitric oxide reading the condition of EGR is unknown.By 246k you might find the engine is done and need of replacement or rebuilding rings, bearings, valve job, valve seals.

Do a compression and leakdown test to verify..................check hot idle oil pressure to evaluate, also.

It has served a long and useful life.

[babysirt]

Since you didn't provide nitric oxide reading the condition of EGR is unknown.By 246k you might find the engine is done and need of replacement or rebuilding rings, bearings, valve job, valve seals.

Do a compression and leakdown test to verify..................check hot idle oil pressure to evaluate, also.

It has served a long and useful life.

I didn't add the NOx readings because I passed those. They were way below the standard. I also passed high speed CO. I only listed the failed readings. I'm going to do a compression test in the morning.

[babysirt]

DAMN

Cyl 1: 178Cyl 2: 179Cyl 3: 145; 155 with some oilCyl 4: 175

And there you have it